1. Field of the Invention
The present invention relates to connectors configured to connect to multiconductor ribbon cable and, in particular, concerns a connector that is configured to connect to conductors within a high density multi-conductor ribbon cable in a more efficient and accurate manner.
2. Description of the Related Art
Ribbon cable is a type of cable which has a plurality of conductors positioned adjacent to each other in a single plane. Typically, conductors are encased in a flexible insulating material, such as vinyl, which follows the contours of the parallel, closely spaced conductors in the ribbon cable. Ribbon cable is often used to interconnect computer components. One common example of the use of ribbon cable is to connect motherboards in personal computers to disk drives. Ribbon cable is also often used to interconnect computers to accessory equipment.
Generally, connectors are used to interconnect the cables to various devices. These connectors have a plurality of contacts which are configured to contact the conductors within the ribbon cable and also to provide a pin connection to a mating connector or printed circuit board. Typically, the connector includes a plurality of contacts that have an insulation displacement end that pierces the insulation surrounding the conductor in the ribbon cable and contacts the embedded conductor, and a mating section that provides a connection point for pins of a mating connector or printed circuit board.
The typical connector is generally rectangular in shape and has an opening which receives the ribbon cable so that the connector spans the width of the ribbon cable. The insulation displacement ends of the plurality of contacts are positioned within the connector so that when the connector is closed around the ribbon cable, the insulation displacement end pierces the insulation surrounding the conductors of the ribbon cable and forms an electrical connection with each of the conductors within the ribbon cable. The contacts are preferably exactly positioned within the connector so as to be able to contact and make an electrical connection with the corresponding conductor within the ribbon cable.
However, currently available connectors for higher density ribbon cables suffer from several problems. One such problem stems from the relatively small size of the conductors and their relatively close position to each other. The tolerances between the contacts in the connector must be very exact to ensure that each contact is being connected to only its' intended conductor. However, the conductors in the cable are also prone to be slightly misaligned as a result of manufacturing tolerances. This can result in the contacts making inadvertent contact with adjacent conductors or not making adequate contact with the intended conductors. Hence, there is a need for a connector that is capable of correctly orienting the conductors with respect to the contacts to ensure better connection between the contact and the conductor.
Moreover, the contacts in the connectors that are configured to be attached to the higher density ribbon cables are generally smaller in size. One difficulty associated with these smaller contacts is that the insulation displacement ends of the contacts are more likely to bend during the attachment of the connector to the ribbon cable. As the conductors within the high density ribbon cables are closer together, this can result in the contacts making electrical connection to conductors other than the intended conductor. Further, as the conductors are positioned closer together, the tolerances in the connector are much smaller. It is important that the conductors of the ribbon cable be exactly aligned with respect to the connector to ensure that the contacts in the connector make good electrical connections to the contacts. Consequently, the higher density ribbon cable connectors that are currently available are less reliable as accurate connection between the contacts and the conductors is more problematic.
Another problem of prior art connectors is that the manufacturing and assembling cost of these connectors is relatively high. Specifically, these connectors typically use multiple rows of contacts that are positioned within the connector in a position where they can connect to corresponding conductors within the ribbon cable. For example, with the old forty conductor ribbon cable, there would be two rows of 20 contacts positioned in the connector so as to connect to the ribbon cable conductors. With the higher density ribbon cables, there is often three or four rows of contacts positioned within the connector to connect to each of the ribbon cable conductors.
The greater the number of rows of contacts in the connector increases the assembly cost of the connector. Specifically, the contacts that are positioned within the connectors are typically provided in rows that are ganged together. If the connector is configured to have more rows of contacts, then more rows of contacts must be positioned into the corresponding receptacles in the connectors. For example, a single prior art connector that connects to a ribbon cable having sixty-eight conductors spaced on 0.025" centers may have four parallel rows of contacts that are spaced on 0.100" centers so that the four separate rows of contacts make electrical contact with the conductors in the ribbon cable. This requires that the assembler of the device position four separate rows of contacts into receptacles formed in the connector during the assembly process. Moreover, there are typically only two rows of mating sections of the contacts that are positioned within the connector so as to be connected to an external connector or printed circuit board. The assembly of a connector having four rows of insulation displacement ends configured to make electrical connection with the ribbon cable, but only two rows of mating sections greatly complicates the assembly of the connector.
Further, the greater number of rows of contacts for each connector also results in a higher manufacturing cost. Specifically, each row of contacts must be plated with a conductive material such as gold. The cost of plating is highly dependent upon linear feet of material to be plated. As each row of contacts have the same length, multiplying the number of rows by four results in a four-fold increase in the plating cost of producing the contacts. Moreover, the overall cost of the connectors is also increased as a result of the greater usage of the base metal forming the contacts.
Hence, there is a need for a connector that is configured to be attached to high density ribbon cables that is less expensive and more reliable than currently available connectors. To this end, there is a need for a connector which is cheaper to manufacture and assemble and is also less likely to be damaged during the installation process in a manner that would result in contacts becoming misconnected to conductors within the high density ribbon cable.